Metallurgy!
Transcript:
Metallurgy is amazing. So, copper is one of the few metals that can be mined in directly usable form. As a consequence, it was the first metal to be made into an alloy. Copper plus around 12% of tin gives bronze. Copper plus zinc gives brass. Going ahead, iron plus carbon gives steel, and steel plus about 11% of chromium makes it stainless steel.
It's amazing how metallurgists figured out the additives, and the additives are usually around 11 to 12 percent, and there is a systematic reason w